Method for providing control data for an ophthalmic surgical laser and treatment device with at least one corresponding ophthalmic surgical laser

Abstract

Method for providing control data for an ophthalmic surgical laser (18) of a treatment device (10), wherein the method comprises the following steps performed by a control device (20): - Determining at least one cross-sectional area (14, 16) in a cornea (26) of a human or animal eye (30), - Defining an incision path (17, 17') which extends from an outer surface of the cornea (26) to at least one of the cut surfaces (14, 16), wherein the incision path (17, 17') has at least two sections (17a, 17b, 17c) with different slope values ​​between the outer surface and the respective cut surface (14, 16), and wherein the incision path (17, 17') terminates at an obtuse angle in the respective cut surface (14, 16), - Providing control data for controlling the ophthalmic surgical laser (18) which includes at least the defined incision path (17, 17'), wherein a path profile with a minimum area is calculated in a cross-section along the optical axis of the eye to define the incision path (17, 17').

Description

[0001] The invention relates to a method for providing control data for an ophthalmic surgical laser of a treatment device. The ophthalmic surgical laser can be used, for example, to perform refractive error correction in a human or animal eye. The ophthalmic surgical laser can, for example, be controlled to detach a corneal volume from the cornea with predefined interfaces. This corneal volume is hereinafter also referred to as a lenticule.

[0002] The invention also relates to a method for controlling a treatment device with at least one corresponding ophthalmic surgical laser, a control device for carrying out the respective method, a treatment device, a computer program and a computer-readable medium.

[0003] Treatment devices and methods for controlling lasers, which are used, for example, to correct refractive errors of the cornea, are known in the prior art. For example, a pulsed laser and a beam focusing device can be configured such that laser beam points within a focus located in corneal tissue cause an optical breakthrough, in particular photodisruption, at a predetermined cut surface. Two such cut surfaces can, for example, define or delimit a lenticule to be removed. Thus, by irradiating the tissue with the laser, the lenticule can be detached from the cornea.

[0004] To extract the detached lenticule from the corneal tissue, an incision is made starting from the outer surface of the cornea. This type of incision is also called a slit. The incision is made to reach the specific cutting surface, or cutting plane.

[0005] The incision is made to access the specific cut surface, for example, the upper and lower boundaries that define the lenticule. It may be necessary to manually refine or recut the cut surface before removing the lenticule to ensure the laser treatment was successful. This allows, for example, the separation of any tissue remnants or bridges left behind by the laser from the surrounding corneal tissue. A medical instrument, particularly a cutting device, can be inserted through the incision and then used to cut along the cut surface. The corneal tissue to be removed can then be extracted through the incision.

[0006] Various types of incisions are known from the prior art. For example, it is possible to make only one incision in the cornea for lenticule extraction. This incision can, for instance, run directly from the outer surface to an intersection of the interfaces bordering the lenticule, or to a cross-sectional surface of the interfaces leading to that intersection.

[0007] From US 2015 / 0 057 644 A1, an ophthalmic surgical device is known by means of which an incision with a straight course is made for the extraction of a lenticule.

[0008] An incision with a straight line allows for the shortest possible length of the cut itself. However, this can create additional edge effects that may worsen the refractive error. For example, an unnecessarily sharp edge between the incision and the respective interface may require more manipulation by medical personnel during lenticule extraction. This can injure or damage the surrounding tissue, or alter its shape. This results in increased stress on the corneal tissue. Overall, this can increase irritation and delay the healing process.

[0009] Alternatively, multiple incisions, for example one incision for each of the interfaces, can be made in the cornea.

[0010] For example, DE 10 2020 112 277 A1 discloses a method for controlling an ophthalmic surgical laser in which two different incisions are made in the cornea to extract a lenticule. The incisions have a curved path.

[0011] Furthermore, DE 10 2007 019 813 A1 discloses a device for creating incisions in the cornea of ​​an eye for the correction of refractive errors. In this device, two spaced-apart incisions are made in the cornea and guided to the lenticule. The incisions contribute to the correction of the refractive error of the eye.

[0012] Furthermore, patent US 6,325,792 B1 describes an ophthalmic surgical laser and a procedure, patent EP 3,988,063 A1 describes an ophthalmic device for surgical treatment of a cornea, patent US 2022 / 0192,882 A1 describes an ophthalmic device for the treatment of a cornea, and patent DE 10,2007,019,814 A1 describes a post-operative treatment following ophthalmic refractive correction.

[0013] Multiple incisions, as known from current techniques, place additional stress on the corneal tissue compared to a single incision. This can lead to increased irritation and a prolonged healing process for the patient. Furthermore, the likelihood of introducing an effect that contributes to refractive error is increased.

[0014] The object of the present invention is to reduce effects contributing to refractive errors when using an ophthalmic surgical laser, and in particular to reduce the degree of invasiveness.

[0015] This problem is solved by the independent patent claims. Advantageous embodiments with expedient further developments of the invention are specified in the respective dependent patent claims. Advantageous embodiments of an independent patent claim are to be regarded as advantageous embodiments for the other independent patent claims, and vice versa.

[0016] Instead of performing an incision that ends in a sharp edge at the respective cut surface, as is done in the prior art, the invention is based on the idea of ​​creating a smooth transition from the incision to the respective cut surface. This allows for more precise guidance for medical personnel when cutting the respective cut surface. Surgical manipulation of the corneal tissue is significantly shortened and is therefore less invasive than the prior art method.

[0017] A first aspect of the invention relates to a method for providing control data for an ophthalmic surgical or ophthalmic laser treatment device. The method comprises the following steps, which can be performed by means of a control device: First, at least one cross-sectional surface is determined as a cutting plane in the cornea of ​​a human or animal eye. Preferably, at least two cross-sectional surfaces, for example, a first and at least a second cross-sectional surface, are defined. The respective cross-sectional surfaces can be located in different planes along the optical axis of the eye, starting from an outer surface of the cornea.Alternatively, the cut surfaces can be arranged, for example, in the same plane along the optical axis, i.e., in particular, side by side. The respective cut surfaces can, for example, form interfaces in a known manner that delimit a lenticule or define the lenticule geometry. That is, the cut surfaces can have one or more points of intersection and / or a cutting plane. The first cut surface can, for example, form a so-called posterior interface, and the second interface can form a so-called anterior interface.

[0018] Subsequently, at least one incision path is defined. The incision path extends from the outer surface, i.e., a surface of the cornea adjacent to its surroundings, to at least one cut surface. The incision path has at least two sections with different slopes between the outer surface and the respective cut surface. Preferably, each pair of adjacent sections has a different slope. That is, the (adjacent) sections run in different directions. The different slopes become apparent particularly in a two-dimensional view of the incision path.

[0019] Furthermore, the incision line terminates or ends at an obtuse angle in the respective cut surface. This means that the respective cut surface and the incision line form an obtuse angle. In other words, at least one segment of the incision line is connected to the respective cut surface at an obtuse angle.

[0020] Finally, the process provides control data for the ophthalmic surgical laser, which includes at least the defined incision path. Specifically, the control data can include the geometry and position of the incision path, i.e., a three-dimensional description of the incision path. Of course, the control data can also additionally or alternatively include the defined cutting surface, i.e., the geometry and position of the respective cutting surface within the corneal volume.

[0021] The control data can also include a data set for positioning and / or focusing individual laser pulses within the cornea. This data set can, for example, contain coordinate values ​​in three-dimensional space representing treatment points or areas for the laser eye surgery. The treatment points collectively define the cutting path. This cutting path can encompass the incision line and the respective cut surface. To remove tissue, the laser beam is focused onto the treatment points within the cornea. This means that the laser beam's energy required for tissue removal is delivered to a specific coordinate point in a desired plane within the cornea. In this way, the respective cut surface and / or the incision line can be traced or irradiated.The coordinate values ​​can be described as coordinates in a suitable coordinate system (Cartesian, polar, cylindrical).

[0022] The control data may additionally or alternatively include a respective data set for setting at least one beam device for beam guidance and / or beam shaping and / or beam deflection and / or beam focusing of a laser beam of the respective laser.

[0023] Furthermore, to determine the incision path, a profile with a minimum area is calculated. The minimum area of ​​the incision can be determined, for example, using the calculus of variations. Due to the typical, well-known geometry of a human or animal eye, the incision with the minimum area usually has a cubic profile.

[0024] This has the advantage that as little corneal tissue as possible is damaged by the incision. As a result, the procedure is less invasive, and potential refractive errors can be further reduced.

[0025] The overall aim is to create a non-straight or non-linear incision, which, due to its obtuse angle, gently joins or borders the respective incision surface. This approach avoids effects that contribute to refractive errors caused by the corneal incision. Furthermore, the method is less invasive, thus reducing the invasiveness of the procedure for the patient. Irritation can be avoided, and the healing process can be accelerated.

[0026] The cut surface can encompass a predefined position and / or geometric description within the cornea. This can be calculated, for example, from refractive error data. The calculation methods used for this are well-known. For example, to remove a lenticule, a refractive power or diopter value to be corrected can be specified, which can then be used to determine the lenticule to be removed. In particular, the "collapse" or closure of the cornea after removal of the lenticule results in the desired correction.

[0027] Preferably, exactly one incision path is specified to reach both cut surfaces. That is, the first and at least the second cut surfaces are preferably connected to each other via an interface. Alternatively, at least one incision path, and in particular two or more incision paths, can be specified. Each of the incision paths can lead to exactly one of the respective cut surfaces.

[0028] The respective incision path, viewed two-dimensionally, essentially describes a line segment or a segment of a line. At one end, the incision path is bounded by an intersection with the respective interface. At the other end, the incision path is bounded by an intersection with the outer surface, i.e., a surface of the cornea that faces the surrounding tissue.

[0029] To achieve the desired shape of the incision pattern, it can be composed of at least two, i.e., two or more, interconnected sections or segments. The individual sections have different slope values ​​or gradients. Here, the slope refers to a measure of the steepness of the section. The slope can also be understood as a measure of the direction or orientation of the section relative to the outer surface or the respective cut surface as a reference surface or plane. The slope value can thus specify the direction for a direction vector that mathematically or geometrically describes the respective section. With respect to a common starting point or origin, for example, an intersection point on the surface or the respective cut surface, the direction vectors of the at least two sections point in different directions.

[0030] Therefore, the incision path is not a straight line overall. Instead, it can describe a curved path or be composed of two or more straight segments. Possible shapes or geometries of the incision path will be discussed in more detail later.

[0031] The section of the incision that ends at the intersection with the cut surface forms, as previously mentioned, an obtuse angle with the cut surface. In this context, an obtuse angle is, in particular, an angle greater than 90° and preferably at most 180°. Preferably, the angle may be, for example, greater than or equal to 120°, more preferably greater than or equal to 140°, and more preferably greater than or equal to 160°.

[0032] In this context, the obtuse angle is always the angle formed by the incision line and the side or outer edge of the respective cut surface facing the outer surface of the cornea. If the cut surface forms, for example, the boundary of a lenticule, as mentioned earlier, the obtuse angle may be determined, for example, by the contour of the lenticule relative to the incision line.

[0033] Further advantages of the invention result from the embodiments described below.

[0034] The following embodiments describe the specific forms that the incision path can take. In particular, the incision path is considered as a two-dimensional function graph, i.e., its course in a cross-section axially to, or along, the optical axis of the eye.

[0035] According to one embodiment, the incision path, starting from the respective cut surface, has a profile that forms a tangent to the respective cut surface, at least in sections. That is, the incision path terminates at a tangent to the respective cut surface. The obtuse angle is therefore approximately 180°. This results in tangential access from the outside for machining the respective cut surface. Thus, a particularly smooth transition between the incision and the cut surface can be achieved.

[0036] According to a further embodiment, the incision path has at least one, preferably exactly one, local extremum. Thus, the incision path can, for example, have a U-shape or a V-shape. The incision can, for example, have a parabolic path. The local extremum can occur at the intersection between the at least two sections. The local extremum can, for example, be a local or global maximum or minimum.

[0037] According to another embodiment, the incision curve includes at least one, preferably exactly one, inflection point. Thus, the incision curve can, for example, have an S-shape or a lightning bolt shape. Here, the inflection point refers to a point of inflection in the mathematical sense. That is, the incision curve includes a change in the curve's shape. Consequently, the curvature of the function graph that describes the incision curve changes. For example, the curvature can change from right to left or vice versa.

[0038] The incision profile can have more than two segments, for example, three. Of these segments, the two adjacent or adjoining segments have different slopes. Accordingly, the incision profile can, for example, consist of three compound or connected straight lines. Alternatively, a straight segment can be connected to a parabolic segment. Alternatively, the incision can, for example, have a cubic profile.

[0039] According to another embodiment, the incision path is described by a parabolic and cubic function. The incision thus follows a curve or a curved path. A function graph describing the incision path can therefore be described by a second-degree or third-degree polynomial. The incision path can thus have a parabolic or cubic shape, i.e., a U-shape or S-shape. The curved path of the incision results in a particularly smooth transition without sharp edges.

[0040] According to another embodiment, the incision, starting from the outer surface, runs at least partially essentially perpendicular to a surface of the cornea, i.e., the outer surface. This means that a section of the incision connected to the outer surface can run at approximately a 90° angle to the outer surface. This ensures that the incision damages as little of the tissue structures, known as fibrils, from which the cornea is composed.

[0041] According to a further embodiment, the incision line preferably runs, at least in sections, substantially parallel to one of several tissue layers of the cornea running parallel to the outer surface. Particularly preferably, the incision line can run in the section between two adjacent such tissue layers. This has the advantage that the smallest possible area of ​​the tissue layers, i.e., the fibrils, is damaged by the incision. The degree of invasiveness of the procedure can be reduced.

[0042] The course or structure of the tissue layers can be estimated based on the known geometry and structure of the cornea, or measured, for example, using known imaging techniques or standard methods. From this, it is possible, for instance, to model how the layers are arranged within the volume of the cornea.

[0043] According to a further embodiment, the incision path can end at the intersection of the first and at least the second cut surface. That is, the incision can be made where the upper and lower cut planes, i.e., the at least two cut surfaces, meet. Thus, both cut surfaces can be accessed via a single incision.

[0044] According to a further embodiment, the laser is suitable for emitting laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 900 nm and 1200 nm, with a pulse duration of between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kilohertz (kHz), preferably between 100 kHz and 100 megahertz (MHz). The use of such lasers in the method according to the invention also has the advantage that the irradiation of the cornea does not have to take place in a wavelength range below 300 nm. This range is referred to in laser technology as "deep ultraviolet." This advantageously avoids unintentional damage to the cornea caused by these very short-wavelength and high-energy beams.Photodisruptive and / or ablative lasers of the type used here typically deliver pulsed laser radiation with a pulse duration between 1 fs and 1 ns into the corneal tissue. Such lasers are known as nanosecond lasers, picosecond lasers, or femtosecond lasers. This allows the power density of the respective laser pulse, necessary for optical breakthrough, to be spatially tightly limited, thus enabling high cutting accuracy when generating the cut surfaces. The wavelength range between 700 nm and 780 nm can also be selected.

[0045] Another aspect of the invention relates to a method for controlling a treatment device. This method comprises the steps of at least one embodiment of the method as previously described. Furthermore, the method for controlling the treatment device includes the step of transmitting the provided control data to at least one ophthalmic or surgical laser of the treatment device.

[0046] The respective procedure may include at least one additional step that is executed precisely when a use case or application situation occurs that is not explicitly described here. This step may, for example, include the output of an error message and / or a prompt for user feedback. Additionally or alternatively, it may be provided that a default setting and / or a predetermined initial state is set.

[0047] Another aspect of the invention relates to a control device configured to perform the steps of at least one embodiment of one or both of the previously described methods. For this purpose, the control device may include a computing unit for electronic data processing, such as a processor. The computing unit may comprise at least one microcontroller and / or at least one microprocessor. The computing unit may be implemented as an integrated circuit and / or a microchip. Furthermore, the control device may include an (electronic) data storage device or a storage unit. Program code, which encodes the steps of the respective embodiment of the respective method, may be stored on the data storage device. The program code may include the control data for the respective laser.The program code can be executed by the processing unit, which then causes the control unit to execute the respective configuration. The control unit can be designed as a control chip or control device. The control unit can, for example, be part of a computer or computer network.

[0048] A further aspect of the invention relates to a treatment device comprising at least one ophthalmic or surgical laser and a control unit configured to perform the steps of at least one embodiment of one or both of the previously described methods. The respective laser can be configured to at least partially separate one or more predefined cut surfaces in the cornea, in particular a predefined corneal volume with predefined interfaces of a human or animal eye, by means of optical breakthrough, in particular by means of photodisruption, and / or to ablate corneal layers and / or to cause a laser-induced change in the refractive index of the cornea and / or the lens of the eye.

[0049] Another aspect of the invention relates to a computer program. The computer program comprises instructions that, for example, constitute program code. The program code can include at least one control data set with the respective control data for the respective laser. When the program code is executed by a computer or a computer network, it is caused to execute the method described above, or at least one embodiment thereof.

[0050] Another aspect of the invention relates to a computer-readable medium (storage medium) on which the aforementioned computer program or its instructions are stored. To execute the computer program, a computer or a computer network can access the computer-readable medium and read its contents. The storage medium is, for example, designed as a data storage device, in particular at least partially as a volatile or non-volatile data storage device. A non-volatile data storage device can be flash memory and / or an SSD (solid-state drive) and / or a hard drive. A volatile data storage device can be RAM (random access memory). The instructions can be, for example, in the form of source code of a programming language and / or as assembly language and / or as binary code.

[0051] Further features and advantages of one of the described aspects of the invention may arise from further developments of another aspect of the invention. The features of the embodiments of the invention can therefore exist in any combination with one another, unless they have been explicitly described as mutually exclusive.

[0052] Additional features and advantages of the invention are described below with reference to the figure(s) in the form of advantageous embodiments. The features or combinations of features of the embodiments described below can be combined with each other and / or with the features of the embodiments. That is, the features of the embodiments can complement and / or replace the features of the embodiments, and vice versa. Therefore, embodiments that are not explicitly shown or explained in the figures, but which can be derived and generated from separate combinations of features in the embodiments and / or embodiments, are also to be considered as encompassed and disclosed by the invention.Thus, embodiments that do not exhibit all the features of an originally formulated claim, or that go beyond or deviate from the combinations of features set out in the references of the claims, are also to be considered disclosed.

[0053] This shows: Fig. 1 a schematic representation of a treatment device for correcting refractive errors in a human or animal eye according to an exemplary embodiment; Fig. 2 a schematic representation of an incision path into a volume of a cornea according to a first exemplary embodiment; Fig. 3 a schematic representation of an incision path into a volume of the cornea according to a further exemplary embodiment; Fig. 4 a schematic representation of an incision path into a volume of a cornea according to a first exemplary embodiment; Fig. 5 a schematic representation of an incision path into a volume of a cornea according to a first exemplary embodiment; Fig. 6 A schematic process flow diagram for providing control data for controlling the treatment device according to an exemplary embodiment.

[0054] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0055] The Fig. Figure 1 shows a schematic representation of a treatment device 10 with an ophthalmic surgical laser 18 for the separation of a lenticule 12 defined by control data from a cornea 26, for example by means of photodisruption and / or ablation. This can, for example, correct a refractive error.

[0056] The figures show the cornea 26 in a cross-section, i.e., a side view, in a plane that runs axially to the optical axis of the eye. The cornea 26 is bounded along an optical axis by an anterior corneal surface 30 and a posterior corneal surface 32. For the separation of the lenticule 12, a posterior or first interface 14 and an anterior or second interface 16 of the lenticule 12 are specified in the control data. A cavitation bubble path can be generated on these interfaces to separate the lenticule 12 from the cornea 26. These interfaces 14 and 16 form cutting surfaces along which a cut can be made to separate the lenticule 12. It can be seen that a control unit 20 for the laser 18 can be provided next to the laser 18, enabling it to emit pulsed laser pulses, for example, in a predefined pattern to generate the interfaces 14 and 16.Alternatively, the control unit 20 can be an external control unit 20 with respect to the treatment device 10.

[0057] Furthermore, the Fig. 1, that the laser beam 24 generated by the laser 18 is deflected towards the cornea 26 by means of a beam deflection device 22, namely a beam deflection device, such as a rotary scanner. The beam deflection device 22 is also controlled by the control device 20 in order to generate the interfaces 14, 16, preferably also incisions or cuts, along predetermined incision paths.

[0058] The laser 18 shown is preferably a photodisruptive and / or ablative laser configured to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, with a pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. The control device 20 optionally also includes a storage device (not shown) for at least temporarily storing at least one control data set, wherein the control data set(s) comprise control data for positioning and / or focusing individual laser pulses in the cornea.The position data and / or focusing data of the individual laser pulses, that is, the lenticule geometry of the lenticule 12 to be separated, is generated on the basis of predetermined control data, in particular from a previously measured topography and / or pachymetry and / or the morphology of the cornea or the optical refractive error correction to be produced.

[0059] To determine refractive error data, which can specify a value in diopters, for example, suitable examination data for describing the refractive error can be received from a data server by the control unit 20, or the examination data can be entered directly into the control unit 20.

[0060] The planning of the correction to be achieved and thus the geometry of the lenticule 12 to be removed is usually carried out according to standard methods, whereby a refractive power correction and / or a lenticule diameter is planned, and the anterior and posterior interface 14, 16 of the lenticule 12 are then determined from this.

[0061] To remove the detached lenticule 12 from the corneal volume 26, an incision or cut with a predetermined incision path can be made using the laser 18, as described above. In the present embodiment, exactly one incision 15 is provided. The incision path 17, i.e., the geometry and position of the incision, can also be included in the control data.

[0062] Preferably, the incision 15 extends from an interface 31 with the outer surface, i.e., the anterior corneal surface 30, to an interface or intersection point 13 where the upper cutting plane and the lower cutting plane, i.e., the first and second interfaces 14, 16, meet (see Fig. 1) Alternatively, the incision 15 can end in an interface 13' with one of the interfaces, in this case for example the first interface 14 (see Fig. 2 to Fig. 5) Starting from the interface 13', the respective boundary surface can, for example, run in the direction of the intersection point 13. This allows both boundary surfaces 14, 16 to be reached via a single cut.

[0063] To avoid further increasing the invasiveness of the procedure through incision 15 and introducing effects that contribute to refractive errors, the shape of incision 15 is of particular importance. In this case, for example, incision 15 has a non-straight or non-linear incision path 17. This means that the incision path 17 can have at least two sections, i.e., two or more sections, with different slopes or gradients. The sections thus run in different directions, for example, starting from the corneal surface 30 as the starting point or reference plane.

[0064] Furthermore, the incision path 17 terminates or opens at an obtuse angle at the intersection point 13 with the respective interface, hereinafter, for example, the first interface 14. The angle at which the incision path 17 meets the respective interfaces 14, 16 is hereinafter also referred to as the adjoining angle α. The adjoining angle α is preferably defined as follows: 90° < α ≤ 180°. In comparison, the angle at which the incision path meets the outer surface is hereinafter referred to as the entry angle Φ. The entry angle Φ is preferably approximately 90°.

[0065] The Fig. Figures 2 to 5 show various advantageous embodiments for an incision path geometry 17. For better clarity, the following are shown in the Fig. 2 to 5, only the one in Fig. Section A of the cornea 26 is shown in section 1. The section shown in the Fig. The geometries or length ratios of the incision lines or their segments shown in Figures 2 to 5 are to be considered examples only. Depending on the requirements, other length ratios or combinations of the aforementioned shapes can, of course, be chosen for the respective incision line. In particular, the incision line may, for example, depend on the structure or composition of the cornea, especially its tissue layers or fibrils. The structure may, for example, be known through the aforementioned measurement methods.

[0066] The Fig. 2 and Fig. Figure 3 shows a multi-part incision. That is, the incision path 17 is composed of several segments or sections, which are formed as straight lines, i.e., essentially straight line segments.

[0067] In the Fig. 2 The incision path 17 comprises, by way of example, three such sections 17a, 17b, 17c. Sections 17a, 17b, 17c are shown in the exemplary embodiment in Fig. 2 is arranged such that the incision path 17 has a U-shaped profile. The incision path 17 therefore does not include any change in arc. Starting from the interface 13', the curvature of the incision path 17 thus runs to the left.

[0068] Section 17a is connected at one end to the interface 31 of the anterior corneal surface 30. Section 17a runs essentially perpendicular to a plane encompassing the anterior corneal surface 30 in the region of the interface 31. That is, the angle of entry Φ is essentially 90°. Such an angle of entry Φ has the advantage of minimizing the area of ​​tissue structures, the so-called fibrils, that make up the cornea 26, that are damaged.

[0069] Section 17c is connected at one end to the first interface 14. The angle of contact α is, in particular, greater than 90°. In the present embodiment, the angle of contact α can, for example, be approximately 160°.

[0070] Sections 17a and 17b are connected to each other via section 17c at their respective opposite ends.

[0071] Fig. Figure 3 also shows a three-part structure consisting of the straight sections 17a, 17b and 17c of the incision path 17. However, in contrast to the embodiment in Fig. 2 in an S-shape or lightning bolt shape. This means that there is a change of arc in the incision path 17. In this case, for example, the incision 15 runs, starting from the interface 13' between sections 17c and 17b, first in a left-hand curve. From section 17b to section 17a, the incision 15 transitions into a right-hand curve. Section 17b includes or forms an inflection point or turning point for the incision path 17, i.e., the point at which the change of arc takes place.

[0072] In Fig. In example 3, the boundary angle α is 120°. The entry angle Φ remains essentially 90°.

[0073] One way to reduce the risk of tissue injury compared to the examples in Fig. 2 and Fig. To further minimize point 3, it is necessary to smooth the course of incision 15. The Fig. 4 and Fig. Figure 5 shows corresponding embodiments for a smooth incision 17. That is, instead of the straight sections 17a, 17b, 17c, the incision 15 comprises a curve or a curved profile. Thus, the incision can be composed of a plurality, preferably infinitely many, points or sections, each having different slopes at least relative to its adjacent section.

[0074] Fig. 4 shows analogous to Fig. 2 a U-shaped course of the incision 15. The incision course 17 can be shown in the exemplary embodiment in Fig. 4, for example, can be described by a parabolic function, i.e., by a second-degree polynomial. To achieve a particularly smooth transition between the respective interface and the incision line 17, the angle of intersection α is approximately 180°. This means that the incision line 17 forms a tangent to the interface 14 at the intersection point 13'. Thus, a tangential approach to the interface 14 is obtained, and the risk of tissue injury during intervention via the incision can be further reduced.

[0075] In Fig. Figure 4 shows another exemplary incision path 17', which also describes a U-shape or parabolic shape. Compared to incision path 17, incision path 17' is curved in the opposite direction. Starting from the interfaces 31, 13', incision path 17 extends to an extremum 19, which describes a local maximum of incision path 17, for example, away from the optical axis of the eye. In contrast, incision path 17' extends from interfaces 31, 13' to an extremum 19', which describes a local maximum of incision path 17', for example, towards the optical axis of the eye.

[0076] Due to its different profile, the incision profile 17' has a boundary angle α' that is more acute than the boundary angle α. For example, the boundary angle α' can be less than 120°, preferably less than 100°. Correspondingly, the entry angle Φ' of the incision profile 17' is larger than the entry angle Φ of the incision profile 17. For example, the entry angle Φ' can be an obtuse angle, and may, for instance, lie between 100° and 140°.

[0077] The incision path 17' can describe a profile of the incision 15 that has a minimal area. Despite the sharper edge at the transition of the incision path 17' to the interface 14, this reduces the invasiveness and the risk of tissue injury, as less tissue is damaged by the incision overall. How to calculate the length and, in particular, the area of ​​a function graph, especially that of the incision path 17, is generally known. To calculate the minimal area of ​​the incision 15, the calculus of variations can be used, for example. This can be solved, for instance, using the well-known Euler-Lagrange equation.

[0078] Fig. 5 shows analogous to Fig. 3. An incision profile with an S-shape. The incision profile 17 can be described by a cubic function, i.e., a third-degree polynomial. The shape of the incision profile 17 is chosen such that the entry angle Φ is 90°. The S-shape thus results in a boundary angle α, which in the present embodiment is approximately 120°.

[0079] Fig. Figure 5 also shows an alternative configuration of the incision path 17', in which the incision path 17', as before, is Fig. As described in section 4, the incision terminates tangentially at the intersection point 13'. The shape of the incision path 17' is unchanged compared to the incision path 17. However, this results in an interface 31' with the anterior corneal surface 30, which is located further away from the optical axis compared to the interface 31. Thus, the angle of incidence Φ' is an obtuse angle. In the present embodiment, the angle of incidence Φ' can be approximately 120°, for example.

[0080] Fig. Figure 6 now shows, in a schematic process flow diagram, an exemplary procedure for providing tax data for the [unclear text]. Fig. 1 shown ophthalmic surgical laser 18 of the treatment device 10. Using the control data, the incision path 17, 17', but also, for example, the interfaces 14, 16, can be specified as described above.

[0081] In the procedure, in step S1, the first and second interfaces 14, 16 are first determined as cutting surfaces or cutting planes in the cornea 26. Then, the incision path 17, 17', as previously described, is determined. The incision path is calculated, for example, such that at least two sections 17a, 17b, 17c with different slope values ​​result, and the incision path 17, 17' terminates or opens at an obtuse angle in the respective interface 14, 16.

[0082] Finally, in step S3, the control data for controlling the ophthalmic surgical laser 18 is provided. This includes at least the defined incision path.

[0083] Overall, the embodiments show a non-straight or non-linear incision as access to one or more planes, i.e. the interfaces 14, 16, within the cornea 26.

Claims

[1] Method for providing control data for an ophthalmic surgical laser (18) of a treatment device (10), wherein the method comprises the following steps performed by a control device (20): - Determining at least one cross-sectional area (14, 16) in a cornea (26) of a human or animal eye (30), - Defining an incision path (17, 17') which extends from an outer surface of the cornea (26) to at least one of the cut surfaces (14, 16), wherein the incision path (17, 17') has at least two sections (17a, 17b, 17c) with different slope values ​​between the outer surface and the respective cut surface (14, 16), and wherein the incision path (17, 17') terminates at an obtuse angle in the respective cut surface (14, 16), - Providing control data for controlling the ophthalmic surgical laser (18) which includes at least the defined incision path (17, 17'), wherein a path profile with a minimum area is calculated in a cross-section along the optical axis of the eye to define the incision path (17, 17'). [2] Method according to claim 1, wherein the incision path (17, 17') starting from the respective cutting surface (14, 16) has at least sectionally a path which forms a tangent to the respective cutting surface (14, 16). [3] Method according to any of the preceding claims, wherein the incision path (17, 17') comprises at least one local extremum (19, 19'). [4] Method according to any of the preceding claims, wherein the incision path (17, 17') includes at least one turning point. [5] Method according to any of the preceding claims, wherein the incision path (17, 17') is described by means of a parabolic or cubic function. [6] Method according to one of the preceding claims, wherein the incision path (17, 17') extends from the outside at least sectionally substantially perpendicular to a surface of the cornea (26). [7] Method according to one of the preceding claims, wherein the incision path (17, 17') is at least sectionally preferably substantially parallel to one of several tissue layers of the cornea (26) running parallel to the outside. [8] Method according to one of the preceding claims, wherein the incision path (17, 17') ends at an intersection (13) of a first and at least a second cutting surface (14, 16). [9] Method according to one of the preceding claims, wherein the laser (18) is controlled by providing the control data by means of the control device (20) to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, at a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz. [10] Method for controlling a treatment device (10) wherein the method comprises the following steps: - the process steps of a process according to one of the preceding claims, and - Transferring the provided control data to a respective ophthalmic surgical laser (18) of the treatment device (10). [11] Control device (20) configured to carry out a respective procedure according to one of the preceding claims. [12] Treatment device (10) comprising at least one ophthalmic surgical laser (18) for introducing predefined cut surfaces (14, 16) into a cornea (26) of a human or animal eye (30) by means of optical breakthrough, in particular by means of photodisruption and / or ablation, and at least one control device (20) according to claim 11. [13] Computer program comprising commands that cause the treatment device (10) according to claim 12 to perform a method according to any one of claims 1 to 9 and / or a method according to claim 10. [14] Computer-readable medium on which a computer program according to claim 13 is stored.

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